地质样品中铍元素分析测试技术研究进展

Recent Advances in Analytical Techniques for the Determination of Beryllium in Geological Samples

  • 摘要: 铍(Be)作为战略性关键金属,其在复杂地质基体中的准确定量分析及赋存状态研究,是阐明成矿机制与开展矿产资源评价的重要技术支撑。由于铍原子序数低、含铍矿物(尤其是硅酸盐矿物)热力学稳定性极强以及基体干扰严重等因素,铍的定量分析长期存在技术难题。本文评述了地质样品中铍元素分析测试中,含铍样品前处理方法、整体含量分析及微区原位分析技术的发展现状与适用范围。含铍矿物如绿柱石、硅铍石等难熔硅酸盐矿物的完全分解,是影响分析结果准确性的关键因素,不同类型矿物需采用针对性的前处理方法。石墨炉原子吸收光谱法(GFAAS)、电感耦合等离子体发射光谱法/质谱法(ICP-OES/MS)是铍元素分析的主要技术手段,可准确测定铍含量为0.018 ~ 100000 μg/g的样品。GFAAS灵敏度高,但属单元素检测,且需要选择适配的基体改进剂以消除干扰;ICP-OES可实现多元素同步测定,但检出限较高,易受光谱干扰;ICP-MS检出限低,可同步测定多元素,但存在质谱干扰。激光剥蚀电感耦合等离子体质谱法(LA-ICP-MS)可在13 μm束斑下测定低至0.200 μg/g的铍含量,与电子探针(EPMA)、激光诱导击穿光谱(LIBS)等技术联合,可共同表征矿物赋存状态与空间分布。当前,铍分析技术已形成整体含量分析与微区原位分析协同互补的体系。单元素分析中,高含量铍适合采用传统化学分析方法,低含量铍则优先采用GFAAS;多元素同步分析以ICP-OES和ICP-MS为主;微区原位分析中,EPMA适用于中高含量铍矿物的定量,LA-ICP-MS适用于低含量铍的高灵敏度测定,LIBS则适用于现场快速半定量筛查。不同方法在检测范围、多元素同步分析能力、空间分辨率及分析尺度方面具有较强的互补性,可满足区域地球化学调查、矿产资源评价及矿物微区表征等研究需求。

     

    Abstract: As a strategic critical metal, beryllium (Be) requires accurate quantification in complex geological matrices and characterization of its occurrence states, which are essential for elucidating metallogenic mechanisms and supporting mineral resource assessments. The quantitative analysis of beryllium has long been challenging due to its low atomic number, the high thermodynamic stability of beryllium-bearing minerals (especially silicate minerals), and severe matrix interference. This review summarizes recent advances in sample pretreatment methods for beryllium-bearing samples, bulk beryllium content analysis, and micro-scale in situ analytical techniques for the determination of beryllium in geological samples. The complete decomposition of beryllium-bearing minerals, particularly refractory silicate minerals such as beryl and phenakite, is a critical factor affecting the accuracy of analytical results. Targeted sample preparation methods are therefore required for different mineral types. Graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma-optical emission spectrometry/mass spectrometry (ICP-OES/MS) are the main analytical techniques for beryllium determination, enabling accurate measurement of beryllium concentrations ranging from 0.018 to 100000 μg/g in samples. Among these techniques, GFAAS exhibits high sensitivity but is limited to single-element determination and requires the selection of appropriate matrix modifiers to eliminate interferences. ICP-OES enables simultaneous multi-element determination but generally has higher detection limits and is susceptible to spectral interferences. ICP-MS provides low detection limits and allows simultaneous determination of multiple elements, but suffers from mass spectral interferences. Laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) enables the determination of beryllium concentrations as low as 0.200 μg/g using a 13 μm laser spot size. Combined with electron probe microanalysis (EPMA) and laser-induced breakdown spectroscopy (LIBS), it allows the simultaneous characterization of beryllium occurrence and spatial distributions. Currently, beryllium analytical techniques have developed into a complementary system integrating bulk concentration analysis and micro-scale in situ analysis. For single-element analysis, conventional chemical analysis methods are suitable for samples with high beryllium concentrations, whereas GFAAS is preferred for low-concentration samples. Multi-element simultaneous analysis mainly relies on ICP-OES and ICP-MS. For micro-scale in situ analysis, EPMA is applicable for the quantitative determination of beryllium in minerals with medium to high concentrations, LA-ICP-MS is suitable for highly sensitive determination of low-level beryllium, and LIBS is applicable for rapid on-site semi-quantitative screening. Different analytical methods exhibit strong complementarity in terms of detection range, multi-element determination capability, spatial resolution, and analytical scale, enabling their application to regional geochemical surveys, mineral resource assessments, and micro-scale characterization of minerals.

     

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